Aluminium or aluminium alloy moulding process lubricant, and aluminium or aluminium alloy plate for moulding processes

ABSTRACT

Lubricants are provided which are aluminium or aluminium alloy plate moulding lubricants, and are lubricants which are easily removed after moulding of aluminium or aluminium alloy plate and assembly; also, bonding and welding can be performed while coated with those lubricants, and the bonding and weld strength obtained are the same as if there were no adhering lubricant. Their main constituents are a polyalkylene oxide or derivative thereof and a higher fatty acid salt. It is preferable if they contain 50 to 2 weight % polyalkylene oxide or derivative thereof, and the ratio of higher fatty acid salt and polyalkylene oxide or derivative thereof is within the range 1/12 to 1/4, and further that they contain water. When these lubricants are formed into a 0.2-2.0 g/m 2  solid film on the surface of the aluminium or aluminium alloy plate, this is suitable for moulding processes.

SPECIFICATION

This Application is a 371 of PCT/JP94/02204, Dec. 22, 1994.

Aluminium or aluminium alloy moulding process lubricant, and aluminiumor aluminium alloy plate for moulding processes.

FIELD OF TECHNOLOGY

This invention concerns processing technology for aluminium or aluminiumalloy plate (below, these are together referred to as Al). Morespecifically, this invention relates to a lubricant which is effectiveduring the moulding of Al products of complex shape which are difficultto process, with Al components which are difficult to mould, for exampleautomobile components, and also electrical equipment components, andaircraft components.

BACKGROUND TECHNOLOGY

Since Al has superior corrosion resistance and mouldability, as well aslightness, it is widely used in many industrial fields, particularly theautomobile industry, as the most universally used metal material, aftersteel materials. Recently, in order to make automobiles lighter, the useof Al plate has gradually been increasing. However, Al plate is moredifficult to mould than steel plate, and easily cracks during moulding;hence there are major problems, such as shape lmitations during design.

Because of this, when pressing Al plate, automobile manufacturers oftenuse liquid lubricating oils or solid lubricants with superiorlubricating properties rather than using the normal mineral oillubricants. The solid lubricants are used to increase press mouldabuityby forming a lubricant film on the Al plate material beforehand. Thus,in the subsequent assembly steps, bonding processes and weldingprocesses are performed on the pressed products without removing thelubricant, and the lubricant is removed in a degreasing step aftercompletion of the assembly steps.

However, with the aforesaid method, because the bonding processes andwelding processes are performed with the lubricant still coated on theproduct after pressing, the residual lubricant causes poor bonding andpoor welding, and as a result productivity may decrease and productquality may deteriorate.

DISCLOSURE OF INVENTION

This invention is made in the light of circumstances such as theaforesaid. The purpose of this invention is to provide lubricants for Alplate moulding, which solve the defects of the previous technology, andalso to provide Al plate for moulding processes. Thus, it provides Alplate moulding lubricants such that degreasing is not difficult whendegreasing is performed after the moulding and assembly processes havebeen finished, and the same bonding strength, weld strength and spotelectrode life are obtained as when no lubricant is adhering to thepress-moulded product in the bonding process and welding process afterthe pressing process, and it provides Al plate for such mouldingprocesses.

In order to achieve the aforesaid purpose, the present inventors carriedout repeated research into Al plate moulding methods, and thus, as aresult of searching for moulding process lubricant compositions that donot worsen the bondability and weldability of the Al plate, made thisinvention.

In one aspect, this invention provides an Al moulding process lubricantcharacterised in that it is an aqueous solution comprising apolyalkylene oxide or derivative thereof, a higher fatty acid salt andwater, among these the polyalkylene oxide or derivative thereofcomprises 2 to 50 weight %, and is contained in an amount 4 to 12 timesthe weight of the higher fatty acid salt, and it forms a solid lubricantfilm on evaporation of the water after coating onto the Al surface.

In another aspect, this invention provides an Al plate for mouldingprocesses, characterised in that a lubricant containing 4-12 weightparts polyalkylene oxide or derivative thereof per weight part higherfatty acid salt is formed onto the surface of the Al plate as a 0.2-2.0g/m² solid film.

The "moulding" referred to above does not only mean moulding by pressingalone, and it includes moulding by drawing or deep-drawing processes,stamping, and extrusion.

This invention is described in detail below.

The moulding lubricant concerned in this invention forms solidlubricating films and has the action of increasing lubrication duringmoulding processes such as press-moulding. Further, since the lubricantfilms formed by this lubricant have superior adhesion with bondingagents and conductivity when high currents are passed, and confersatisfactory bonding strength and weld strength in the assembly process,it is possible to restrict to a minimum poor bonding and poor weldsformed as aforesaid because of lubricants. Also, this lubricant has goodmouldability and degreasability, and causes no reduction in mouldabilityand degreasability compared to the lubricants previously used byautomobile manufacturers.

Further, the Al plate for moulding processes concerned in this inventionhas a lubricant film formed by coating the aforesaid lubricant onto theAl plate surface. The lubricant film formed is superior in adhesion withbonding agents and in conductivity when high currents are passed, andconfers satisfactory bonding strength and weld strength in the assemblyprocess. Hence by means of this invention, the bondability andweldability can be improved, while maintaining the mouldability of thesolid lubricant.

Next, defining factors for the lubricants of this invention are shownbelow.

As polyalkylene oxides or derivatives thereof, for examplepolyoxyethylene, oxyethylene oxypropylene (block) polymer, ethyleneoxide propylene oxide (block) additive of ethylenediamine,polyoxyethylene stearyl ether, polyoxyethylene oleyl ether,polyoxyethylene cetyl ether, polyoxyethylene castor oil ether,polyoxyethylene stearate, polyoxyethylene oleate, polyoxyethylenelaurate, etc., may be mentioned. Of course, they are not limited tothese. Among them, polyoxyethylene and polyoxyethylene stearyl ether arepreferably used. Also, polyalkylene oxides or derivatives thereof whichare solid at normal temperature and of melting point 115° C. or beloware preferable, and those of melting point 50-100° C. are especiallydesirable.

As higher fatty acid salts, for example sodium salts, potassium salts orother salts of stearic acid, palmitic acid, myristic acid, lauric acid,arachic acid, behenic acid, myristoleic acid, palmitoleic acid, oleicacid, linolic acid, linolenic acid, eleostearic acid, hydroxystearicacid, ricinolic acid, castor oil fatty acids, coconut oil fatty acids,beef tallow fatty acids, mutton tallow fatty acids, etc., may bementioned. Of course, they are not limited to these. Also, as thelubricating properties of higher fatty acid salts vary depending on thenumber of carbons, it is preferable to use those with 8-24 carbons, andespecially desirable to use those with 12-20 carbons.

Through the combined use of the aforesaid two components as the mainconstituents, improvements in adhesion of bonding agents with thelubricant, degreasability and weld strength, and improvements inmouldability and uniformity of welds, etc., are achieved.

Provided that these components are contained as the main constituents,other additives or diluents can be incorporated as appropriate. Forexample, when using diluted with water, the following composition isdesirable.

That is to say, when using by diluting these main constituents in water,if the weight of polyalkylene oxide or derivative thereof is more than50 weight %, the viscosity of the lubricant becomes too high, and has anadverse effect on workability when coating onto the Al plate.Conversely, with less than 2 weight %, a satisfactory lubricant filmafter drying is not obtained. Hence, when using diluted with water, 50weight % or less and 2 weight % or more of the polyalkylene oxide orderivative thereof is preferable.

In this case, with a composition ratio of higher fatty acid salt andpolyalkylene oxide or derivative thereof less than 1/12, a tendency isseen for the mouldability in the pressing process after coating onto theAl plate and drying to be insufficient; also, if the composition ratiois higher than 1/4, there tend to be adverse effects on degreasabilityin the assembly process. Hence it is desirable for the composition ratioof higher fatty acid salt and polyalkylene oxide or derivative thereofto be in the range 1/12 to 1/4. That is to say, it is desirable to use a4-12 fold weight of the polyalkylene oxide or derivative thereof, perweight part of higher fatty acid salt.

Also, water acts as a diluent for polyalkylene oxides or derivativesthereof and higher fatty acid salts and evaporates into the atmosphereafter coating. With diluents other than water, for example organicsolvents, atmospheric pollution will be caused after evaporation.Consequently, it is desirable to use water as the diluent. Ordinarytap-water may be used as the water, but in order to prevent formation ofinsoluble salts it is preferable to use deionised water or distilledwater.

There are no particular restrictions as to other additives, anddepending on the purpose of use the following additives can be used. Forexample, antioxidants such as 2,6-di-t-butylparacresol,tetramethyldiaminodiphenylmethane and zinc dithiophosphate,anticorrosion agents such as dinonylnaphthalenesulphonates, phosphateesters, thiophosphate esters, α-mercaptostearic acid, benzoate salts andsorbitan monooleate, oiliness improvers such as higher fatty acids,higher alcohols, fatty acid esters and higher amines, extreme-pressureagents such as dibenzyl sulphide, chlorinated paraffins, triallylphosphate, lead naphthenate and molybdenum isobutyl xanthate, anddetergent dispersants such as naphthenate salts and calciumcetylphenate, etc., may be mentioned. These additives can be added up to10% of the total contained weight of the polyalkylene oxide orderivatives thereof and higher fatty acid salts which are the mainconstituents. If that amount or more is added, caution is necessarysince there is a risk that it will cause a decrease in degreasability.

Next, the reasons for the numerical limitations on the lubricant filmwhen the aforesaid lubricant is coated onto Al plates are explained.

If the amount of lubricant film is greater than 2.0 g/m², the degreasingin the degreasing process after completion of the assembly processbecomes incomplete and the lubricant is not completely removed, andcauses poor painting in subsequent painting processes. Further, withless than 0.2 g/m², the mouldability during the pressing process isinsufficient, causing cracking to occur. Consequently, the amount ofsolid lubricant film coating after drying is set in the range 0.2-2.0g/m².

Also, the aforesaid lubricant is sometimes coated directly onto thesurface of the Al plate for example by hot-melting, but for the sake ofworkability it is normally preferable to use it in such a way as to forma solid lubricant film by diluting with water, coating onto the Al platefor example with a roller-coater, and drying. When water is used, careshould be taken since if the amount of solids is too great the viscositybecomes high and it cannot be coated with a roller-coater, andconversely if the amount of solids is too low a sufficient amount oflubricant film cannot be obtained after coating, and it is for examplenecessary to apply two coats, and either of these can cause a worseningin workability.

Also, when the aforesaid lubricants are used diluted with water, itbecomes necessary to dry the lubricant, but there is no particularrestriction on the drying method. For example, it can be dried byleaving at room temperature, but in terms of productivity it isdesirable to dry it by blowing hot air.

Further, there is also no particular restriction as to the materialquality of the Al plate which is the moulding material. The Al plate maybe made of aluminium, and also may commonly be made of an aluminiumalloy. As the Al plate, it is possible to use material with suitablecomponents and composition selected on the basis of the requirements forthe final product. For example, if a high-strength material is required,an Al/high-Mg (3-6% Mg) type can be used.

PRACTICAL EXAMPLES

Next, practical examples of this invention are presented.

Practical Example 1

Using the 8 different lubricant compositions No. 1 to No. 8 shown intable 1, 0.5 g/m² lubricant films were formed on test pieces by coatingthese onto the test pieces, then drying by keeping 5 minutes in a 70° C.thermostatic chamber. Further, those shown in No. 9 to No. 16 in table 1are lubricants outside the range of this invention, but lubricant filmswere formed in the same way using these lubricants. Using the testpieces thus obtained, the mouldability during press-moulding,degreasability from the pressing process to the assembly process,bondability in the assembly process, weldability in the assembly processand workability when coating the lubricant were assessed. The testpieces and assessment methods used for this are as follows.

The tests were performed with n=3, and the mean values of these weretaken; the lubricants were coated using a roller-coater. Further, if thelubricant had a high content of solids other than water, and coating wasimpossible as the viscosity was too high, it was coated (hot-melt) afterlowering the viscosity by heating the lubricant. If the lubricant had alow solids content and it was impossible to coat the specified amount ofsolids in a single operation with the roller-coater, the coating withthe roller-coater was performed twice.

A Test Pieces

JIS 5182-O material, of plate thickness 1 mm, was used.

B Lubricants

As shown in table 1, a total of 16 different lubricants, 8 differentlubricants corresponding to the practical examples of this invention and8 different lubricants outside this invention, were prepared and used.

                                      TABLE 1                                     __________________________________________________________________________    Constituents of Lubricant Test Samples                                           Lubricant                                                                  No.                                                                              Composition                          Remarks                               __________________________________________________________________________    1  Polyoxyethylene 1.4% + sodium stearate 0.2% + water 98.4%                                                          Examples                              2  Polyoxyethylene 7% + sodium stearate 1% + water 92%                                                                of this                               3  Polyoxyethylene 17.5% + sodium stearate 2.5% + water                                                               Invention                             4  Polyoxyethylene 52.5% + sodium stearate 7.5% + water 40%                   5  Polyoxyethylene 17.5% + sodium stearate 2.5% + naphthenic acid salt 1%        + water 79%                                                                6  Polyoxyethylene stearate 17.5% + potassium stearate 2.5% + water 80%       7  Polyoxyethylene oleyl ether 17.5% + potassium oleate 2.5% + water 80%      8  Polyoxyethylene laurate 17.5% + potassium oleate 2.5% + water 80%          9  Polyoxyethylene 15% + sodium stearate 5% + water 80%                                                               Comparative                           10 Polyoxyethylene 18.75% + sodium stearate 1.25% + water                                                             Examples                              11 Polyoxyethylene 20% + water 80%                                            12 Oxyethylene oxypropylene block copolymer 20% + water 80%                   13 Polyoxyethylene stearate 20% + water 80%                                   14 Potassium stearate 10% + water 90%                                         15 Sodium oleate 20% + water 80%                                              16 Hardened animal wax 17% + surfactant 3% + water 80%                        __________________________________________________________________________

C Assessment Methods

(1) Mouldability

Using an Erichsen tester, the following square tube drawing test wasperformed, with assessment on the basis of the maximum moulding heightbefore cracks occurred.

Blank diameter: □ 100 mm

Punch diameter: □ 40 mm square head (punch R 4.5 mm, die R 3.0 mm)

Process speed: 20 mmimin

Assessment criteria: ◯ 10.0 mm or more

Δ less than 10.0 mm, 9.0 mm or more

X less than 9.0 mm.

(2) Degreasability

After immersing for 2 minutes in alkaline sodium silicate typedegreasing liquid (pH=10.5, 430° C.±2° C.), assessment was by thepercentage area wetted by water after removing and water washing.

Assessment criteria: ◯ 80% or more

Δ less than 80%, 50% or more

X less than 50%.

(3) Bondability

Using a commercial epoxy structure adhesive, the tests were performed onthe basis of the adhesive tensile shear test method specified in JISK6850.

Assessment criteria: ◯ 1500 N/cm² or more

Δ 1400 N/cm² or more, less than 1500 N/cm²

X less than 1400 N/cm².

(4) Weldability

Continuous spot testing during spot-welding was performed. The strengthat the time of the spot was based on the test method of JIS Z 3136, andassessment was based on the number of continuous spot-welded spots untilthe time when the strength reached 1500 N or less.

Assessment criteria: ◯ 300 spots or more

Δ less than 300 spots, 160 spots or more

X less than 160 spots.

(5) Workability

If coating was possible using the roller-coater once, the workabilitywas regarded as good (◯), and if it was impossible with one coating, andhot-melting or two coatings were performed, the workability was regardedas unsatisfactory (Δ).

The results of the assessments of mouldability, degreasability,bondability, weldability and workability in the practical examples andcomparative examples were as shown in table 2. In the comparativeexamples, where the lubricants Nos. 9-16 of table 1 were used, becausethe lubricant compositions are outside the range specified in thisinvention, there were defects in that one or more of mouldability,degreasability, bondability and weldability were inferior.

In contrast to this, in the practical examples, where the lubricantsNos. 1-8 of table 1 were used, a balance of mouldability,degreasability, bondability and weldability is obtained. This is due tothe fact that the composition ratio of polyoxyethylene and sodiumstearate in the lubricants is within the range 1/4 to 1/12. Now, withthe aforesaid composition ratio 1/4 or more as in comparative example 9,the degreasability decreases, and with 1/12 or less as in comparativeexample 10, there is a tendency for the mouldability and bondability todecrease.

Practical Example 2

Using the lubricant shown as No. 3 in table 1, the amounts coated ontothe same test pieces as were used in practical example 1 were varied,and the mouldability and degreasability of the test pieces wereinvestigated. That is to say, as a result of varying the amount of solidlubricant coating as shown in table 3, the mouldability anddegreasability results shown in table 3 were obtained.

                                      TABLE 2                                     __________________________________________________________________________    Performance of Test Lubricants                                                Mouldability            Bondability                                                                            Weldability                                  Square Tube    Degreasing Ability                                                                     Shear    Number of Workability                        Lubricant                                                                          Drawing                                                                             Assess-                                                                           Wet  Assess-                                                                           Strength                                                                           Assess-                                                                           Continuous                                                                          Assess-       Assess-                  No.  Height (mm)                                                                         ment                                                                              Area (%)                                                                           ment                                                                              (N/cm.sup.2)                                                                       ment                                                                              Spots (Spots)                                                                       ment                                                                              Coating Method                                                                          ment                                                                              Remarks              __________________________________________________________________________    1    10.9  ◯                                                                     100  ◯                                                                     1650 ◯                                                                     560   ◯                                                                     Roller-coater, 2                                                                        Δ                                                                           Examples             2    10.9  ◯                                                                     100  ◯                                                                     1650 ◯                                                                     560   ◯                                                                     Roller-coater                                                                           ◯                                                                     of this              3    10.8  ◯                                                                     90   ◯                                                                     1650 ◯                                                                     500   ◯                                                                     Roller-coater                                                                           ◯                                                                     Invention            4    10.9  ◯                                                                     90   ◯                                                                     1650 ◯                                                                     640   ◯                                                                     Hot melt  Δ                  5    10.7  ◯                                                                     85   ◯                                                                     1600 ◯                                                                     700   ◯                                                                     Roller-coater                                                                           ◯            6    10.4  ◯                                                                     85   ◯                                                                     1530 ◯                                                                     500   ◯                                                                     Roller-coater                                                                           ◯            7    10.2  ◯                                                                     85   ◯                                                                     1600 ◯                                                                     700   ◯                                                                     Roller-coater                                                                           ◯            8    10.3  ◯                                                                     85   ◯                                                                     1530 ◯                                                                     500   ◯                                                                     Roller-coater                                                                           ◯            9    11.3  ◯                                                                     60   Δ                                                                           1600 ◯                                                                     200   Δ                                                                           Roller-coater                                                                           ◯                                                                     Comparative          10   9.4   Δ                                                                           100  ◯                                                                     1450 Δ                                                                           660   ◯                                                                     Roller-coater                                                                           ◯                                                                     Examples             11   8.7   X   100  ◯                                                                     1790 ◯                                                                     380   ◯                                                                     Roller-coater                                                                           ◯            12   9.7   Δ                                                                           70   Δ                                                                           1810 ◯                                                                     120   X   Roller-coater                                                                           ◯            13   9.2   Δ                                                                           95   ◯                                                                     1710 ◯                                                                     100   X   Roller-coater                                                                           ◯            14   11.4  ◯                                                                     30   X   1150 X    80   X   Roller-coater                                                                           ◯            15   11.5  ◯                                                                     20   X   1320 X   100   X   Roller-coater                                                                           ◯            16   12.1  ◯                                                                      0   X    330 X    40   X   Roller-coater                                                                           ◯            __________________________________________________________________________

                                      TABLE 3                                     __________________________________________________________________________    Relationship Between Amount of Coating Lubricant and Mouldability/Degreasi    ng Ability                                                                    Coating Amount of                                                                         Mouldability  Degreasing Ability                                     Solid Lubricant                                                                        Square Tube                                                                             Assess-                                                                           Wet Area                                                                           Assess-                                        No.                                                                              (g/m.sup.2)                                                                            Drawing Height (mm)                                                                     ment                                                                              (%)  ment                                                                              Remarks                                    __________________________________________________________________________    1  0.1       8.9      X   100  ◯                                                                     Comparative Example                        2  0.5      10.8      ◯                                                                     90   ◯                                                                     Example of this Invention                  3  1.0      12.4      ◯                                                                     80   ◯                                                                     Example of this Invention                  4  2.5      15.0      ◯                                                                     20   X   Comparative Example                        __________________________________________________________________________

The results were that in the comparative example test No. 1 in table 3,the mouldability was poor since the amount of coating was low, and inthe comparative example test No. 4, the degreasability was poor sincethe amount of coating was large. In contrast to this, in the practicalexample tests No. 2 and No. 3, the result was that both mouldabllity anddegreasability were superior since the amount of coating was correct.

Since, as explained in detail above, through this invention goodmouldability is achieved for Al, and moulding becomes possible even intoshapes for which press-processing was previously difficult, and also itbecomes possible to improve the degreasability, bondability andweldability after moulding, there are very significant benefits whichwill contribute to the broadening of the applications for Al plate.

APPENDIX A

Lubricant No. 1:

Lubricant composition having less than 2%, by weight, polyalkylene oxideWorkability deficient (Δ).

Lubricant No. 4:

Lubricant composition having greater than 50%, by weight, polyalkyleneoxide Workability deficient (Δ).

Lubricant No. 9:

Lubricant composition having polyalkylene oxide in an amount less than 4to 12 times the weight of the higher fatty acid salt.

Decreasing ability deficient (Δ).

Workability deficient (Δ).

Lubricant No. 10:

Lubricant composition having polyalkylene oxide in an amount greaterthan 4 to 12 times the weight of the higher fatty acid salt.

Moldability deficient (Δ).

Bondability deficient (Δ).

Lubricant No. 11:

Lubricant composition without higher fatty acid salt.

Moldability deficient (X).

Lubricant No. 12:

Lubricant composition without polyalkylene oxide and higher fatty acidsalt.

Moldability deficient (Δ).

Decreasing ability deficient (Δ).

Weldability deficient (X).

Workability deficient (Δ).

Lubricant No. 13:

Lubricant composition without a polyalkylene oxide and a higher fattyacid salt.

Moldability deficient (Δ).

Weldability deficient (X).

Lubricant Nos. 14-16:

Lubricant compositions without a polyalkylene oxide.

Decreasing ability deficient (X).

Bondability deficient (X).

Weldability deficient (X).

What is claimed is:
 1. Aluminium or aluminium alloy moulding processlubricant comprising an aqueous solution of a polyalkylene oxide orderivative thereof, a higher fatty acid salt and water, wherein thepolyalkylene oxide or derivative thereof comprises 2 to 50 weight % ofthe lubricant, and is contained in an amount 4 to 12 times the weight ofthe higher fatty acid salt, said solution forming a solid lubricant filmon evaporation of the water after coating onto an aluminium or aluminiumalloy surface.
 2. Aluminium or aluminium alloy plate for mouldingprocesses, comprising an aluminium or aluminium alloy plate and alubricant containing 4-12 weight parts polyalkylene oxide or derivativethereof per weight part higher fatty acid salt on the surface thereof asa 0.2-2.0 g/m² solid film.
 3. The lubricant according to claim 2,wherein said polyalkylene oxide or derivative thereof is a solid at roomtemperature and has a melting point of 115° C. or below.
 4. Thelubricant according to claim 3, wherein said polyalkylene oxide orderivative thereof has a melting point of 50-100° C.
 5. The lubricantaccording to claim 2, wherein said polyalkylene oxide or derivativethereof is polyoxyethylene or polyoxyethylene stearyl ether.
 6. Thelubricant according to claims 2, wherein said higher fatty acid saltcontains from 8-24 carbon atoms.
 7. The lubricant according to claim 6,wherein said higher fatty acid salt contains from 12-20 carbon atoms. 8.The lubricant according to claim 2 wherein said water is deionized ordistilled water.
 9. The lubricant according to claim 2, furthercomprising up to 10% by weight of the total combined weight of thepolyalkylene oxide or derivatives thereof and higher fatty acid salts,of additives selected from the group consisting of anti-oxidants,anticorrosive agents, oiliness improvers, extreme pressure agents,detergent dispersants and mixtures thereof.
 10. The lubricant accordingto claim 9, wherein said anti-oxidants are selected from the groupconsisting of 2,6-di-t-butylparacresol, tetramethyldiaminodiphenylmethane, and zinc dithiophosphate.
 11. The lubricant according to claim9, wherein said anti-corrosion agents are selected from the groupconsisting of dinonylnaphthalenesulphonates, phosphate esters,thiophosphate esters, α-mercaptostearic acid, benzoate salts andsorbitan monooleate.
 12. The lubricant according to claim 9, whereinsaid oiliness improvers are selected from the group consisting of higherfatty acids, higher alcohols, fatty acid esters and higher amines. 13.The lubricant according to claim 9, wherein said extreme-pressure agentsare selected from the group consisting of dibenzyl sulphide, chlorinatedparaffins, trialkyl phosphate, lead naphthenate and molybdenum isobutylxanthate.
 14. The lubricant according to claim 9, wherein said detergentdispersants are selected from the group consisting of naphthenate saltsand calcium cetylphenate.